Apparatus for forming concrete and transferring loads between concrete slabs

ABSTRACT

An embodiment configured according to principles of the invention of an apparatus for forming concrete includes a form having a slot configured to closely receive a plate in only one direction. An embodiment configured according to principles of the invention of an apparatus for transferring a load between a first concrete slab and a second concrete slab, defining a joint, includes a plate having a first portion and a second portion, wherein the second portion has a first segment and a second segment that is larger than the first segment.

REFERENCE TO EARLIER APPLICATION

This Application incorporates by reference and is a National Phase ofInternational Patent Application No. PCT/US06/004487, filed Feb. 9,2006.

BACKGROUND OF THE INVENTION

Conventional concrete pavement installation involves preparing thenpositioning forms around an area intended for pavement. The forms havevertical inner surfaces to receive and contain poured concrete. Theforms have horizontal top surfaces, which typically are level with thesurface of the poured concrete, or, once cured, pavement surface. Theforms have back surfaces that rest against appropriately-spaced stakesfor holding the forms in place. To provide clearance for finishtroweling, concrete workers often field cut chamfers between the top andback surfaces of the forms.

Very large pavements require substantial form preparation andpositioning. This is especially true if stock materials for forms areshort and/or flexible. Short and flexible forms require more stakingthan longer, more rigid forms to ensure true, unwavy pavement edges.Short forms also require more setup time for chamferring. Regardless ofwhether the forms are long or short, field chamferring requiresconsiderable time for large pavement areas.

Ideally, the forms used for receiving poured concrete should have a trueheight for providing a true slab thickness. Unfortunately, forms in thefield typically have a height that is less than a true height for anappropriate slab thickness. These forms of inadequate height typicallymay be positioned so that the top surfaces are at an appropriate heightrelative to the desired pavement surface height, but present bottomsurfaces that do not contact, thus admit gaps through which pouredconcrete leaks. This wastes concrete and requires additional work toremove the excess portions.

Concrete leakage from the forms, especially at the butt joints, leavesdepressions in a finished slab surface causing poor aesthetics. Thedepressions also impair surface coverings, such as tile, because theuneven surface promotes uneven or incomplete covering layout andadhesion. Cured leaked concrete also impinges on adjacent slabs causingvoids and/or increasing the chances of obtaining a locked construction,which leads to cracks and joint failures. Finally, removing the curedexcess typically damages the slab from which the excess is chiseled.Thus, avoiding form leaks is highly desirable.

Unfortunately, none of the foregoing provides a method of formingconcrete and an apparatus for same that includes stiff, infinitely long,pre-chamferred forms with predetermined true height.

In construction of concrete pavements for highways, airport runways,large warehouse buildings and the like, preventing random cracking ofthe concrete necessitates dividing the pavement into convenient slabsections. To this end, concrete workers pour a monolithic concrete slabthat is allowed to set for a short period. Then, the workers cuttransverse grooves, having a depth on the order of one-fourth of theslab thickness, across the slab, with spacing between cuts selected inaccordance with the application and design. Spacings from 12 to 40 feetare common for highway pavements.

As the concrete of the slab cures, forces derived from the exothermalcuring reactions cause generally vertical cracks to develop through theslab thickness at the reduced cross-sections below each groove. Thiscontrolled cracking effectively divides the slab into predeterminedseparate slab sections.

The vertical cracks or joints define adjacent and interlocking facesformed by the cement and aggregates in the concrete. The interlockingfaces transfer vertical shear stresses among adjacent slab sections, aphenomenon commonly referred to as “aggregate interlock,” as heavyobjects, such as motor vehicles, pass over the joint.

Aggregate interlock causes wear among slab intersections with increasinguse of the pavement. Additionally, cyclical and extreme temperaturechanges decrease slab volumes. Thus, over time, as traffic continuouslypasses over a joint, the intersections wear and become smooth, then failaltogether, resulting in relative vertical displacement of adjacent slabsections, hence a rough pavement surface. Joint failure also becomesincreasingly susceptible to water intrusion, which may freeze and causedamage among adjacent slabs.

To discourage relative vertical displacement among adjacent slabs, priorart techniques provide for implanting dowels in concrete extendingacross the joint intersections. Some dowels are smooth steel rods withdiameters on the order of one inch and lengths of two feet. Each rod iscoated or otherwise treated so that it will not bond to concrete alongits length or at least on one end thereof. Thus, as a slab expands andcontracts during curing and subsequently with temperature changes, thedowel is free to move horizontally relative to, yet maintain verticalalignment of adjacent slabs, augmenting the aggregate interlock totransfer vertical shear stresses across the joints. See, for example,U.S. Pat. No. 3,397,626, issued Aug. 20, 1968, to J. B. Kornick et al.for Plastic Coated Dowel Bar for Concrete and U.S. Pat. No. 4,449,844,issued May 22, 1984, to T. J. Larsen for Dowel for Pavement Joints.

Among other problems, the foregoing techniques involve significant timeand labor to produce and place the dowels.

Another technique to discourage relative vertical displacement amongadjacent slabs involves embedding square-shaped load plates in adjacentslabs with opposed corners of the load plate aligned with the joint. Toavoid shrink- or thermally-induced stress creation between the plate anda slab, concrete workers first embed a blockout sheath in one verticaljoint face for receiving a load plate. To this end, the workers nailonto a form a mounting plate, from which a blockout sheath extends, thenposition the form to receive poured concrete. Once the concrete is curedand bonded to the blockout sheath, the workers remove the form board andleave the blockout sheath in place. Then the workers insert a load plateinto the blockout sheath. Finally, the workers pour an adjacent slab,which bonds to the exposed portion of the load plate. See, for example,U.S. Pat. No. 6,354,760 ('760 patent), issued Mar. 12, 2002, to Boxallet aL, for System for Transferring Loads Between Cast-in-Place Slabs,which is incorporated by reference herein.

Drawbacks of the foregoing include the cost and labor associated withproducing separate mounting and load plates, then assembling samefollowing curing of a first concrete slab.

Referring to FIG. 13, a concrete floor 1100 typically is made up of aseries of individual blocks or slabs 1102-1 through 1102-6 (collectively1102). The same is true for sidewalks, driveways, roads and the like.Blocks 1102 provide several advantages, including relief of internalstress due to drying shrinkage and thermal movement. Adjacent blocks1102 meet at joints 1104-1 through 1104-7 (collectively 1104). Joints1104 typically are spaced so that each block 1102 has enough strength toovercome internal stresses that otherwise would cause random stressrelief cracks. In practice, blocks 1102 should be allowed to moveindividually, but also should be able to transfer loads from one blockto another block.

Transferring loads between blocks 1102 usually is accomplished withsmooth steel rods, also referred to as dowels, embedded in two blocks1102 defining joint 1104. For instance, FIG. 14 shows a side view ofdowel 1200 between slabs 1102-4 and 1102-5. FIG. 15 shows across-sectional view along line XV-XV in FIG. 14 of several dowels 1200spanning joints 1104 between slabs 1102. Typically, a dowel or bar 1200is approximately 14 to 24 inches long, has either a circular or squarecross-sectional shape, and a thickness of approximately 0.5-2 inches.Such circular or square dowels are capable of transferring loads betweenadjacent slabs 1102, but have several shortcomings.

U.S. Pat. Nos. 5,005,331, 5,216,862 and 5,487,249, issued to Shaw etaL., which are incorporated by reference herein, disclose tubular dowelsreceiving sheaths for use with dowel bars having circularcross-sections.

Referring to FIG. 16, a shortcoming of circular or square dowels is thatif dowels 1200 are misaligned, or not perpendicular to joint 1104, theycan undesirably lock the joint together causing unwanted stresses thatcould lead to slab failure in the form of cracking. Such misaligneddowels can restrict movement in the directions 1400-1 and 1400-2.

Another shortcoming of square and round dowels is that they typicallyallow slabs to move only along the longitudinal axis of the dowel. Asshown in FIG. 17, movement is allowed in direction 1500, parallel todowels 1200, while movement in other directions 1502-1 and 1502-2, anddirections into and out from the page is restrained. Such restraint ofmovement in directions other than parallel to the longitudinal axes ofdowels 1200 could result in slab failure in the form of cracking.

U.S. Pat. No. 4,733,513 ('513 patent) issued to Shrader et al.., whichis incorporated by reference herein, discloses a dowel bar having arectangular cross-section and resilient facings attached to the sides ofthe bar. As disclosed in column 5, at lines 47-49 of the '513 patent,such bars, when used for typical concrete paving slabs, would have across-section on the order of ½ to 2-inch square and a length on theorder of 2 to 4 feet.

Referring to FIGS. 18 and 19, yet another shortcoming of prior art dowelbars is that, under a load, only the first 3-4 inches of each dowel bartransfers the load. This creates very high loadings per square inch atthe edge of slab 1102-2, which can result in failure 1600 of theconcrete below dowel 1200, as shown in FIGS. 18 and 19. Such a failurealso could occur above dowel 1200.

Unfortunately, none of the foregoing provide a method of formingconcrete and an apparatus for same that includes partially coated loadplates carried in slotted forms.

What are needed, and not taught or suggested in the art, are a method offorming concrete and an apparatus for same that provide partially coatedload plates carried in pre-slotted, stiff, infinitely long,pre-chamferred forms with predetermined true height that: (1) increaserelative movement between slabs in a true direction parallel to thelongitudinal axis of the joint; (2) reduce loadings per square inchclose to the joint; (3) maximize material at the joint for transferringloads between adjacent cast-in-place slabs efficiently; (4) minimize rawmaterials needed in a load plate; and (5) promote exact load platepositioning to foster better perpendicular and parallel alignment withthe joint and upper concrete surface.

SUMMARY OF THE INVENTION

The invention overcomes the disadvantages noted above by providing amethod of forming concrete and an apparatus for same that providepartially coated load plates carried in pre-slotted, stiff, infinitelylong, pre-chamferred forms with predetermined true height. An embodimentconfigured according to principles of the invention of an apparatus forforming concrete includes a form having a slot configured to closelyreceive a plate in only one direction.

An embodiment configured according to principles of the invention of anapparatus for transferring a load between a first concrete slab and asecond concrete slab, defining a joint, includes a plate having a firstportion and a second portion, wherein the second portion has a firstsegment and a second segment that is larger than the first segment.

The invention provides improved elements and arrangements thereof, forthe purposes described, which are inexpensive, dependable and effectivein accomplishing intended purposes of the invention.

Other features and advantages of the invention will become apparent fromthe following description of the preferred embodiments, which refers tothe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in detail below with reference to thefollowing figures, throughout which similar reference characters denotecorresponding features consistently, wherein:

FIG. 1 is an environmental perspective view of an embodiment of anapparatus for forming concrete configured according to principles of theinvention shown adjacent to concrete;

FIG. 2 is a top front right side elevational view of another embodimentof an apparatus for forming concrete and transferring loads betweenconcrete slabs configured according to principles of the invention;

FIG. 3 is cross-sectional detail view, drawn along line 3-3 in FIG. 2;

FIG. 4 is a plan view of a plate of the embodiment of FIG. 2;

FIG. 5 is a schematic view of an embodiment of a method of making anapparatus configured according to principles of the invention;

FIG. 6 is a schematic view of an embodiment of a method of formingconcrete configured according to principles of the invention;

FIG. 7 is a plan view of an embodiment of an apparatus for formingconcrete and transferring loads between concrete slabs configuredaccording to principles of the invention, shown partially incross-section;

FIG. 8 is a plan view of another embodiment of an apparatus fortransferring loads between concrete slabs configured according toprinciples of the invention;

FIG. 9 is a plan view of a portion of the embodiment of FIG. 8 receivedin a concrete slab, a dashed-line outline of a diamond-shaped platebeing superimposed thereon;

FIGS. 10 and 11 are perspective views of the embodiment of FIG. 1receiving the embodiment of FIG. 8;

FIG. 12 is a top view of the embodiment of FIG. 1 receiving theembodiment of FIG. 8, shown partially in cross section;

FIG. 13 is a plan view of a plurality of concrete slabs defining apavement;

FIG. 14 is a vertical cross-sectional detail view of adjacent concreteslabs and an interposed prior art dowel;

FIG. 15 is cross-sectional detail view drawn along line XV-XV in FIG.14;

FIG. 16 is an enlarged horizontal cross-sectional detail view of aplurality of concrete slabs with interposed prior art dowels that aremisaligned;

FIG. 17 is an enlarged horizontal cross-sectional detail view of aplurality of concrete slabs with interposed prior art dowels;

FIG. 18 is a vertical cross-sectional detail view of adjacent concreteslabs and an interposed prior art dowel wherein one slab exhibits afailure;

FIG. 19 is a cross-sectional detail view drawn along line XVIV-XVIV inFIG. 18;

FIG. 20 is a plan view of a further embodiment of an apparatusconfigured according to principles of the invention;

FIG. 21 is a cross-sectional detail view drawn along line XXI-XXI inFIG. 20;

FIG. 22 is an environmental perspective view, shown partially incross-section, of yet another embodiment of an apparatus fortransferring loads between concrete slabs configured according toprinciples of the invention and a concrete slab prepared for receivingsame;

FIG. 23 is a cross-sectional detail view of yet a further embodiment ofan apparatus for transferring loads between concrete slabs configuredaccording to principles of the invention received in a concrete slab;

FIG. 24 is a schematic view of an embodiment of a method of formingconcrete configured according to principles of the invention;

FIG. 25 is a schematic view of an embodiment of a method of installing aload transfer apparatus configured according to principles of theinvention.

FIG. 26 is a top front right side elevational view of another embodimentof an apparatus for forming concrete and transferring loads betweenconcrete slabs configured according to principles of the invention;

FIG. 27 is a top front right side elevational view of another embodimentof an apparatus for forming concrete and transferring loads betweenconcrete slabs configured according to principles of the invention;

FIG. 28 is a schematic view of an embodiment of a method of formingconcrete configured according to principles of the invention;

FIG. 29 is a schematic view of an embodiment of a method of formingconcrete configured according to principles of the invention;

FIG. 30 is a top front right side elevational view of another embodimentof an apparatus for forming concrete and transferring loads betweenconcrete slabs configured according to principles of the invention;

FIG. 31 is an enlarged side elevational view of a form of the embodimentof FIG. 30;

FIG. 32 is a top front right side elevational view of another embodimentof an apparatus for forming concrete and transferring loads betweenconcrete slabs configured according to principles of the invention;

FIGS. 33 and 34 are plan views, partially in cross-section, of anotherembodiment of an apparatus for forming concrete and transferring loadsbetween concrete slabs configured according to principles of theinvention, respectively before and after proper assembly;

FIG. 35 is a plan view of the embodiment of FIGS. 33 and 34 improperlyassembled; and

FIGS. 36-67 are successive plan and side elevational views of additionalembodiments an apparatus for transferring loads between concrete slabsconfigured according to principles of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention includes an apparatus for and method of forming concreteand transferring loads between concrete slabs that provide partiallycoated load plates carried in pre-slotted, stiff, infinitely long,pre-chamferred forms with predetermined true height.

Referring to FIG. 1, an embodiment of an apparatus for forming concreteconfigured according to principles of the invention includes a form 100.Form 100 has a side surface 105, a top surface 110, a back surface 115and a bottom surface 120. Side surface 105 and back surface 115 define awidth 125 ranging from 0.875 to 2.500 inches. Top surface 110 and bottomsurface 120 define a height 130 ranging from 3 to 18 inches or more,depending on the thickness required for pavement.

Form 100 has a chamfer 135 between top surface 110 and back surface 115.Chamfer 135 defines an angle 140 relative to top surface 110 rangingfrom 10° to 89°, preferably 22.5° to 45°. Side surface 105 and chamfer135 define a top surface width 143 ranging from 0.125 to 0.875 inch.Chamfer 135 provides clearance for trowels and other finishing tools andallows for faster concrete finishing.

Width 125, height 130, angle 140 and top surface width 143 vary asneeded to provide a desired overall stiffness of form 100. Formstiffness dictates the amount of staking required to maintain form 100in place against the great weight of poured concrete 155. Stiffer forms100 require less staking, thus less labor to place forms 100 whereneeded.

More importantly, form stiffness impacts the trueness of an edge 145defined by side surface 105 and top surface 110, which forms acorresponding edge in concrete 155 when cured. Good trueness isimportant to the overall appearance of a pavement defined by multipleslabs having adjacent edges. For example, if an edge of one slab haspoor trueness and is adjacent to another slab edge that has poortrueness, the gap defined between the un-true edges will exhibitunsightly non-uniformity, or portions of the gap that may be too narrowfollowed by portions that may be too wide. This gap non-uniformitycontributes to an overall non-professional image of the area andassociated business.

Preferably, form 100 is constructed of oriented strand board (OSB). OSBstock may be manufactured to assume virtually any dimension, which maybe machined, as described below, to define forms 100 of virtually anylength. As the invention is intended for constructing large-scalepavements, forms 100 with very large lengths are desirable because fewerabutting forms 100 are needed to define a continuous side surface 105and edge 145, hence slab side. This reduces the labor needed to limitand/or treat discontinuities that may occur in the slab side. OSB stockalso is preferred because it may be machined to define a desired height130. This eliminates the occurrence of concrete leaks between the bottomsurface of prior art forms of inadequate height and the supportingsurface underlying the concrete.

Form 100 also may be constructed of dimensional lumber, particle board,metal, plastic, cardboard, fiber board, polyurethane foam, Styrofoam®,or other rigid synthetic or other suitable materials commensurate withthe purposes described herein.

A release overlay 160 is disposed on side surface 105. Release overlay160 is constructed of phenolic paper, kraft paper, acrylic, latex,melamine, Formica®, foil, oil, high density overlay, metal, wood veneeror other suitable material that provides a smooth, closed-celledsurface, substantially free of pores for retaining poured concretewithout adhering to or marring the finished surface thereof when curedand separated from form 100. The foregoing materials may be combined todefine release overlay 160, such as a wood veneer that normally would beoiled.

Referring to FIG. 2, another embodiment of an apparatus for formingconcrete configured according to principles of the invention includes aform 200 and one or more load transfer apparatuses or plates 300 fortransferring loads that are received in form 200. Form 200 isconstructed similarly to form 100 and has slots 260 for receiving plates300. Slots 260 have a spacing 261 of about two feet, or other dimensionsuitable for purposes described herein.

Referring to FIG. 3, each slot 260, preferably, is formed by plungecutting with a rotary saw blade (not shown). Slot 260 is defined byannular surfaces 263, each having curvatures corresponding to the radiusof the plunge-cutting saw blade. Annular surfaces 263 and side surface205 (comparable to side surface 105 of form 100) define opposed proximalintersections 265. Annular surfaces 263 and back surface 215 (comparableto back surface 115 of form 100) define opposed distal intersections270.

Referring to FIG. 4, each plate 300, preferably, is constructed of steelor any material, metallic or non-metallic, that is suitable for a loadtransfer device between adjacent concrete slabs in a pavement. Toeconomize production costs, plate 300 may be shear-cut. Plate 300 has apreferred thickness ranging from 0.1875 through 0.375 inches and sidedimensions 303 of approximately 4.5 inches, or other dimension suitablefor purposes described herein. Preferably, plate 300 has a length 305that is greater than or equal to a width 310. Thus, plate 300, in planview, assumes the shape of a rhombus or square.

Plate 300 has a first portion 315 and a second portion 320, delineatedby a plane 321, defined by the intersections of sides 322 and 323, thatis aligned with side surface 205. First portion 315 may be untreated.Second portion 320 has an elastomer coating 325 configured to adhere toplate 300 only enough to prevent elastomer coating 325 from separatingfrom plate, for example during shipping, but when emplaced, may adhereto concrete, but not to plate 300. Elastomer coating 325 is constructedof polymers, grease or other materials suitable for the purposesdescribed herein.

In practice, when a first concrete slab adheres to elastomer coating 325on second portion 320 and a second concrete slab adheres to firstportion 315, lateral movement among the slabs, due to shrinkage, etc.,will not cause localized stresses because the first and second slabs arenot fixed to plate 300, rather, one slab is permitted to move relativeto plate 300 because it is adhered to elastomer coating 325. Whileelastomer coating 325 originally adheres to plate 300 when plate 300 ismanufactured, curing concrete exerts forces on elastomer coating 325which urges elastomer coating 325 to slide relative to plate 300 onceinstalled.

Alternative embodiments of elastomer coating 325: (1) adhere to plate300, but not to concrete, thereby allowing concrete to slide relative tothe coating; or (2) do not adhere to plate 300 or concrete, therebyallowing concrete to slide relative to plate 300 and/or the coating.

Referring again to FIG. 2, first portion 315 is received in slot 260.Preferably, slot 260 has a tolerance of 0.03125 inch among horizontalsurfaces of slot 260 and first portion 315. This close tolerancingpromotes closely receiving first portion 315 in slot 260. This providesfor maintaining plate 300 at a desired attitude. Elastomer coating 325is likely to have a thickness exceeding this tolerance that wouldprevent slot 260 from receiving second portion 320.

Referring to FIGS. 3 and 4, plate 300 is configured such thatintersections of sides 322 and 323 at the widest extremes of plate 300mate with proximal intersections 265 of form 200. This configurationpromotes a gap-free junction between plate 300 and form 200 thatdiscourages concrete from seeping therethrough. This ensures thatconcrete only contacts elastomer coating 325 and not plate 300.

Plate 300 also is configured, and the radius of a saw (not shown) usedfor plunge cutting slot 260 is selected, such that distal intersections270 in form 200 firmly cradle first portion 315. This configurationprevents plate 300 from undesired rotation or movement relative to form200 despite significant forces exerted on plate 300 by concrete whenpoured on form 200 and plate 300.

Referring to FIG. 7, another embodiment of an apparatus for transferringloads between concrete slabs configured according to principles of theinvention is a plate 700 that has a first portion 715 and a secondportion 720 delineated by a plane 721. First portion 715 may beuntreated. Second portion 720 has an elastomer coating 725 that issimilar to elastomer coating 325.

In practice, first portion 715 is received in a slot 860 in a form 800in a direction aligned with a side 730 extending along first portion 715and second portion 720. Coating 725, having a preferred thickness ofabout 0.03 inches, or a thickness sufficient to prevent second portion720 from passing through slot 860. Coating 725 may be compressible toallow a cured slab (not shown) adhered thereto to move somewhat relativeto second portion 720 along a joint between adjacent slabs (not shown).

Referring to FIG. 8, another embodiment of an apparatus for transferringloads between concrete slabs configured according to principles of theinvention is a plate 900 that has a hexagonal shape. Plate 900 haselongated bases 930, each with adjacent sides 935. Preferably, each base930 and side 935 define an angle 940 of about 100°. Angle 940 may exceed100° in any amount that maximizes the material and/or stress dissipationnearest the joint between concrete slabs.

As with the embodiments described above, plate 900 has a first portion915 and a second portion 920 delineated by a plane 921. First portion915 may be untreated. Second portion 920 has an elastomer coating 925that is similar to elastomer coating 325.

In practice, when a first concrete slab adheres to elastomer coating 925on second portion 920 and a second concrete slab adheres to firstportion 915, lateral movement among the slabs will not cause localizedstresses because the first and second slabs are not fixed to plate 900,rather, one slab is permitted to move relative to plate 900 because itis adhered to elastomer coating 925.

Referring to FIG. 9, plate 900 is shown received in the vertical face ofa concrete slab. The hexagonal geometry of plate 900, as compared with adiamond-shaped plate D, as shown in dashed lines in FIG. 9, providesmore support material 945 at a joint between concrete slabs. This is dueto the preferred 1000 angle between base 930 and side 935, whichprovides nearly 18% additional support material over that provided by adiamond-shaped plate D.

Hexagonally-shaped plate 900 allows for faster and more efficient stressdissipation at the joint. This is because a hexagonal plate presentsmore perimeter in areas of high stress concentration in a cement slab.This allows for reducing the material thickness needed in a load plate,which saves material costs and machine wear. For example, a plate 900interposed between four-inch slabs having a compressive strength of 3000pounds-per-square-inch need only have a 3/16-inch thickness, whereas adiamond-shaped plate must have at least a ¼-inch thickness. Reducedplate thickness also promotes plate yield before concrete failure. Anadvantage of this is that, under great loading, plate 900 yields, ratherthan causing failure in the adjacent concrete slabs plate 900 tiestogether. Thus, the vertical relationship of slabs still is contained,without catastrophic concrete failures that would require slabreplacement.

Another advantage of hexagonally-shaped plate 900 relative to adiamond-shaped plate is that concrete tends to consolidate better underplate 900 because plate 900 presents less area under which concreteflows. This reduces the potential for pockets and voids forming underplate 900, which could lead to joint failure or ineffective loadtransfer.

A further advantage of plate 900 is that plate 900 presents surfacesthat are more stable, or less likely to move, during pouring ofconcrete. This assures that the load plate will assume proper placementand orientation relative to the joint, thus is more likely to perform asintended.

Referring to FIGS. 10 and 11, as with plate 300, plate 900 is intendedto be received in slot 260 in form 200.

Referring to FIG. 12, plate 900 is configured such that intersections ofsides 935 define a widest extreme of plate 900 that mate with proximalintersections 265 of form 200. This configuration promotes a gap-freejunction between plate 900 and form 200 that discourages concrete fromseeping therethrough. This ensures that concrete only contacts elastomercoating 925 and not plate 900.

Plate 900 also is configured, and the radius of a saw (not shown) usedfor plunge cutting slot 260 is selected, such that distal intersections270 in form 200 firmly cradle first portion 915. This configurationprevents plate 900 from undesired rotation or movement relative to form200 despite significant forces exerted on plate 900 by concrete whenpoured on form 200 and plate 900. The hexagonal shape of plate 900renders plate 900 more stable in, and less prone to moving relative toform 200 than diamond-shaped plates during pouring.

Referring to FIGS. 20 and 21, a further embodiment of an apparatus fortransferring loads between concrete slabs is a plate 1000 having edgebanding 1005. While plate 1000 may assume any geometry appropriate foran installation, preferably plate 1000 is constructed similarly to plate900, having a first portion 1015 and a second portion 1020 delineated bya plane 1021. First portion 1015 may be untreated.

Edge banding 1005 preferably is disposed on vertical surface 1007 and/orvertical surface 1009 of second portion 1020 of plate 1000. Preferably,surfaces 1007 and 1009 are not parallel with plane 1021, hence the jointbetween concrete slabs when emplaced. While not excluded from the scopeof the invention, in practice, edge banding 1005 has not been found tobe needed along surfaces parallel to the joint. Abutting concrete slabswill compress each other in a direction perpendicular to the joint, but,absent joint failure, will not compress plate 1000 excessively or to thepoint of joint failure. Thus, little benefit may be realized fromemploying a plate that is compressive in a direction perpendicular tothe joint.

However, abutting concrete slabs do move relatively along the joint.This imparts great shear forces on interslab load plates. To reducethese shear forces and provide greater horizontal relative slabmobility, edge banding 1005 is compressive and resilient. Edge banding1005 may be constructed of any material to obtain these characteristics,but preferably is constructed of a natural polymer and/or syntheticpolymer.

Edge banding 1005 is configured so as to reduce interslab shear forces,provide great horizontal relative slab mobility or other desiredfunctionality in consideration of slab sizing, concrete composition,shrinkage expectations and other emplacement considerations. Inpractice, edge banding 1005 with a thickness 1030 ranging from 0.025 to0.25 inches has been found to perform optimally.

Preferably, second portion 1020 has an elastomer coating 1025 that issimilar to elastomer coating 325. Elastomer coating 1025 also coats edgebanding 1005. Similar to elastomer coating 325, while edge banding 1005originally adheres to plate 1000 when plate 1000 is manufactured, curingconcrete exerts forces on elastomer coating 1025 and edge banding 1005that urges sliding among one or more of elastomer coating 1025, edgebanding 1005 and plate 1000 once installed.

Plate 1000 is well suited for very large concrete slab installations inwhich the slabs require great degrees of horizontal freedom. Withoutthis added mobility, the slabs can “lock up” and develop one or morecracks parallel to the joint anywhere from a foot therefrom to thecenter of the slab.

As with plate 300, plate 1000 is intended to be received in slot 260 inform 200.

Yet another embodiment of an apparatus for transferring loads betweenconcrete slabs configured according to principles of the invention is aplate 1000 that includes independent edge banding (not shown) disposedon surfaces 1011 and/or 1013 of first portion 1015. Once installed incured concrete, edge banding (not shown) may slide relative to plate1000 and/or the cured concrete as needed.

Referring to FIGS. 22 and 23, yet a further embodiment of an apparatusfor transferring loads between concrete slabs configured according toprinciples of the invention is a dowel 1100 that has edge banding 1105with or without an elastomer coating 1115, as described above. Dowel1100 may be constructed from 5/16-2-inch square or round stock 1110 in12-inch lengths.

While dowel 1100 is configured in accordance with industry norms forretrofitting an existing concrete slab to receive a load plate, theinvention is not limited to square or round stock. The invention alsoincludes plunge-cutting or otherwise slotting an existing concrete slabfor receiving epoxy and any of the plates described herein, with orwithout edge banding or an elastomer coating.

Referring to FIG. 5, an embodiment of a method 400 of making anapparatus for forming concrete configured according to principles of theinvention includes: a step 405 of providing a sheet; a step 410 ofdisposing a release overlay on the sheet; a step 415 of cutting thesheet into a plurality of forms; and a step 420 of cutting a chamfer ineach of the plurality of forms.

Step 405 of providing a sheet of material includes material suitable forperforming as a concrete form, preferably OSB stock material. However,the material may be dimensioned lumber, particle board, steel and othersuitable materials if commensurate with the purposes described herein.OSB material is preferred because it can assume virtually any width,length or thickness that may be machined into forms of appropriate, truedimensions for defining the desired pavement. The length of thematerial, ideally, should be as long as the longest side of the pavementdesired. However, manufacturing material that is, e.g. two miles long,is problematic for contemporary manufacturers.

Step 410 of disposing a release overlay on the sheet includes an overlaythat is suitable for retaining poured concrete without adhering theretoor marring the finished surface thereof when the concrete cures and isseparated from the form.

Step 415 of cutting the sheet into a plurality of forms ties into step405 in that the material to be cut should be selected to maximize thenumber of forms machined and minimize any scrap not suitable to be aform. The number of forms derived from the sheet depends on thethickness of pavement desired, which dictates the height of the formsneeded. Ideally, the width of the sheet of material provided in step 405should be an even multiple of the form height, plus some allowance forcutting.

Step 420 of cutting a chamfer in each of the plurality of forms involvesmachining each form derived from step 415 with a chamfer machine thatcuts chamfers in board stock. The chamfer may assume any angle suitablefor purposes described herein, but preferably ranges from 22° to 45°.Step 420 provides tremendous labor savings over prior art techniques andmaterials. Ordinarily, concrete workers field cut chamfers into concreteforms on site, which consumes considerable time. Providing workers withpre-chamfered forms eliminates this on-site step and allows for fastercompletion of the paving job at hand.

Referring to FIG. 6, an embodiment of a method 500 of forming concreteconfigured according to principles of the invention includes: a step 505of providing a plate with a plate coating disposed on a first portionthereof; a step 510 of providing a form having a slot configured toreceive a second portion of the plate; a step 515 of inserting thesecond portion in the slot; a step 520 of positioning the form toreceive concrete; a step 525 of pouring a volume of concrete against theform and the first portion; a step 530 of curing the volume of concreteand defining cured concrete; and a step 535 of removing the form fromthe cured concrete, wherein the plate remains in the cured concrete.

Step 505 of providing a plate with a plate coating disposed on a firstportion thereof involves preparing a plate 300 as described above. Anelastomer coating, configured to adhere to concrete, but not to theplate, is disposed on the first portion of a plate.

Step 510 of providing a form having a slot configured to receive asecond portion of the plate involves plunge cutting the side surface ofa form with a rotary blade having a pre-determined radius selectedaccording to the configuration of the plate received in the slot, asdescribed above.

Step 515 of inserting the second portion in the slot represents asignificant cost savings over prior load plate installation apparatusesand methods. Rather than attaching to a form a mounting plate andblockout sheath, then, after the slab has cured, removing the form whilebreaking free the blockout sheath followed by inserting a load plate inthe blockout sheath, the present method embeds a load plate directlyinto the concrete slab as it cures. Once the concrete cures, the formsare removed with the load plate already embedded in the concrete and nofurther installation required.

Step 520 of positioning the form for receiving concrete also representsan advance over many typical concrete pouring techniques in use. Becausethe forms are precisely cut prior to being staked around the desiredpavement area, they present a true height from support surface topavement surface. This deters concrete from leaking through any gap thatoften exists between the support surface and the bottom surface ofinadequately sized prior art forms.

Step 525 of pouring a volume of concrete against the form and the firstportion and step 530 of curing the volume of concrete and defining curedconcrete are conventional, thus described no further.

Step 535 of removing the form from the cured concrete wherein the plateremains in the cured concrete, as described above, represents asignificant departure from current practices. Once the concrete cures,the forms are removed with the load plate already embedded in theconcrete. Other methods require detaching a form from a mounting platepreviously attached thereto, then installing a load plate in the pocketformed in the concrete.

Referring to FIGS. 22-24, an embodiment of another method 1200 offorming concrete configured according to principles of the inventionincludes: a step 1205 of providing a plate having a first portion and asecond portion and edge banding disposed on a surface of the firstportion; a step 1210 of providing a form having a slot configured toclosely receive the second portion; a step 1215 of inserting the secondportion in the slot; a step 1220 of positioning the form to receiveconcrete; a step 1225 of pouring a volume of concrete on the form andthe first portion; a step 1230 of curing the volume of concrete anddefining cured concrete; and a step 1235 of removing the form from thecured concrete.

Step 1205 of providing a plate having a first portion and a secondportion and edge banding disposed on a surface of the first portioninvolves preparing a plate 1000 as described above. As shown in FIGS. 20and 21, edge banding 1005, with or without elastomer coating 1025, isdisposed on vertical surface 1007 and/or vertical surface 1009 of plate1000.

Steps 1210, 1215, 1220, 1225, 1230 and 1235 are similarto steps 510,515, 520, 525, 530 and 535 above.

Referring to FIG. 25, an embodiment of a method 1300 of installing aload transfer apparatus configured according to principles of theinvention includes: a step 1305 of developing a recess in a concreteslab; and a step 1310 of introducing a first portion of a load transferapparatus in the recess.

Step 1305 of developing a recess typically involves developing a recessin an existing concrete slab adjacent to which a second concrete slab isintended. As shown in FIGS. 22 and 23, dowel 1100 represents an industrystandard for retro-fitting an existing concrete slab to receive a loadplate. Thus, to accommodate a square or round dowel 1100, step 1305would involve boring or reaming a hole in the concrete slab. However,method 1300 is not limited to dowel 1100, and may include any plates ordowels described herein or not described, but appropriate for use inretro-fitting an existing concrete slab to receive a load plate formaintaining vertical alignment relative to a concrete slab to be pouredan adjacent thereto. Therefore, step 1305 may involve plunge-cutting orotherwise developing a slot in the concrete for receiving a plate.

Preferably, following step 1305, method 1300 includes filling the recesssufficiently with an epoxy or suitable material for bonding the dowel orplate to the concrete.

Step 1310 of introducing a first portion of a load transfer apparatus inthe recess preferably involves a dowel or plate that has edge bandingand/or an elastomer coating as described above. The concrete workerwould have to take care that the epoxy adheres only to the edge bandingand/or an elastomer coating and not to the untreated portion of thedowel or plate. Once the epoxy cures, and a second concrete slab may bepoured so as to encapsulate the untreated portion of the dowel or plate.The edge banding and/or elastomer coating permits the slabs to movehorizontally along and perpendicularly to the joint therebetween.

An embodiment of a method 1400 of adapting existing and freshly-pouredconcrete slabs for transferring a load therebetween configured accordingto principles of the invention includes: a step 1405 of installing aload transfer apparatus in an existing concrete slab according to method1300; and a step 1410 of pouring a second volume of concrete on a secondportion of the load transfer apparatus.

Step 1405 of installing a load transfer apparatus in the existingconcrete slab is described above with respect to method 1300.

Step 1410 of pouring a second volume of concrete adjacent to the curedconcrete and on a second portion of the load transfer apparatus involvesencapsulating only the untreated end of dowel or plate.

Referring to FIGS. 26 and 27, another embodiment of an apparatus forforming concrete and transferring loads between concrete slabsconfigured according to principles of the invention includes a form1500, one or more load transfer apparatuses or plates 1600 fortransferring loads between concrete slabs closely received in form 1500,and a like number of sheaths 1700 closely received on each plate 1600.

Preferably, form 1500 is constructed similarly to form 200 with slots1560 comparable to slots 260 for receiving plate 1600.

Plate 1600 is constructed similarly to plate 300. However, rather thanhaving an elastomer coating 325, sheath 1700 is selectably installableon plate 1600. Sheath 1700 may be constructed similarly to the blockoutsheath described in the '760 patent.

Alternatively, sheath 1700 may be constructed of material and/orconfigured to allow: (1) concrete to slide relative thereto; and/or (2)plate 1600 to slide relative thereto. Sheath 1700 should have sufficientintegrity to permit a concrete worker to handle and install sheath 1700on plate 1600 or form 1500, withstand pouring concrete thereon, andperform the functions described above.

Sheath 1700 may include a mounting plate 1705, as shown in FIG. 26, andas described more fully with respect to the blockout sheath and mountingplate described in the '760 patent.

Referring to FIG. 28, an embodiment of another method 1800 of formingconcrete configured according to principles of the invention includes: astep 1805 of providing a plate configured to transfer a load betweenconcrete slabs; a step 1810 of providing a form having a slot configuredto closely receive a first portion of the plate; a step 1815 ofpositioning the form to receive concrete; a step 1820 of inserting thefirst portion in the slot wherein a second portion of the plate isexposed; a step 1825 of pouring a first volume of concrete on the formand the second portion; a step 1830 of curing the first volume ofconcrete and defining a first slab; a step 1835 of removing the formfrom the first slab and exposing the first portion; and a step 1840 ofdisposing a sheath on the first portion.

Step 1805 of providing a plate configured to transfer a load betweenconcrete slabs involves preparing a plate 1600 as described above. Plate1600 may, but preferably does not, include an elastomer coating and/oredge-banding as described above.

Step 1810 of providing a form having a slot configured to closelyreceive a first portion of the plate, preferably, involves plungecutting the side surface of a form with a rotary blade having apre-determined radius selected according to the configuration of theplate received in the slot, as described above.

Step 1815 of positioning the form to receive concrete is comparable tostep 520 above.

Step 1820 of inserting the first portion in the slot wherein a secondportion of the plate is exposed is comparable to step 515 above in thatit represents a significant cost savings over prior load plateinstallation apparatuses and methods. While this embodiment employs ablockout sheath, neither time nor accuracy are sacrificed positioningthen attaching the blockout sheath as in prior applications. Rather, theblockout sheath is installed on a plate that already is properlypositioned in a cured concrete slab.

Steps 1825 and 1830 are conventional and described no further.

Step 1835 of removing the form from the first slab and exposing thefirst portion is comparable to step 535 above.

Step 1840 of disposing a sheath on the first portion, preferably,involves placing on the plate a blockout sheath as described in the '760patent. However, a sheath may assume any form appropriate for thefunction desired, specifically, to allow the concrete slab to moverelative to, or prevent bonding with the plate. To this end, the sheathsimply may be a coating of grease or other debonding agent known in theart. The sheath also could be constructed of an elastomer coating,somewhat as described above, but configured with sufficient integrity soas to allow for installation on a plate without disintegration.

Referring to FIG. 29, an embodiment of another method 1900 of formingconcrete configured according to principles of the invention includes: astep 1905 of providing a plate configured to transfer a load betweenconcrete slabs; a step 1910 of providing a form having a slot configuredto closely receive a first portion of the plate; a step 1915 ofpositioning the form to receive concrete; a step 1920 of inserting thefirst portion in the slot wherein a second portion of the plate isexposed; a step 1925 of disposing a sheath on the second portion; step1930 pouring a first volume of concrete on the form and the sheath; anda step 1935 of curing the first volume of concrete and defining a firstslab.

Steps 1905, 1910, 1915 and 1920 are comparable to steps 1805 1810, 1815and 1820 above.

Step 1925 of disposing a sheath on the second portion is comparable tostep 1840 above with the only difference being that, in step 1840, theplate is in cured concrete, while in step 1925, the plate is in a form.

Step 1930 pouring a first volume of concrete on the form and the sheathis comparable to step 1825 above with the only difference being that, instep 1825, concrete directly contacts the plate, while in step 1930, theconcrete directly contacts the sheath.

Step 1935 is conventional and described no further.

Referring to FIGS. 30 and 31, another embodiment of an apparatus forforming concrete and transferring loads between concrete slabsconfigured according to principles of the invention includes a form 2000and one or more sheaths 2100, with or without mounting plates 2105 asshown in FIG. 30, for mounting on form 2000, preferably at predeterminedintervals. A like number of load transfer apparatuses or plates (notshown) for transferring loads between concrete slabs are configured tobe closely received in each sheath 2100 once disposed in cured concreteand form 2000 is separated therefrom.

Sheath 2100 is similar to sheath 1700 and optional mounting plate 2105is similar to optional mounting plate 1705. Where sheath 2100 does notinclude mounting plate 2105, sheath 2100 defines a proximal outerperimeter 2110. Where sheath 2100 includes mounting plate 2105, mountingplate 2105 defines a proximal outer perimeter 2115.

Unlike form 200, form 2000 does not have slots comparable to slots 260for receiving plate 1600. Rather, form 2000 has slots 2060 configured tomate with or closely receive a portion of outer perimeter 2110 whensheath 2100 is configured without optional mounting plate 2105. Whensheath 2100 is configured with optional mounting plate 2105, slot 2060is configured to mate with or closely receive outer perimeter 2115 ofmounting plate 2105.

Slots 2060 are spaced according to load conditions anticipated for theload plates (not shown) ultimately installed in adjacent concrete slabs.With either embodiment, form 2000 mates with sheath 2100 (or mountingplate 2105) such that only the outer surface thereof contacts concretewhen poured thereon. Once the concrete here's, and form 2000 is removed,sheath 2100 remains embedded in the cured concrete with the interiorexposed for receiving a plate (not shown). Thereafter, another volume ofconcrete may be poured adjacent to the previously cared slab containingsheath 2100 and on the plate, thereby providing for load transferbetween the adjacent slabs.

The plate (not shown) intended for use with this embodiment isconfigured similarly to plate 1600 and described no further.

Referring to FIG. 32, another embodiment of an apparatus for formingconcrete and transferring loads between concrete slabs configuredaccording to principles of the invention includes a form 2200 and one ormore sheaths 2300 for mounting on form 2200, preferably at predeterminedintervals. A like number of load transfer apparatuses or plates (notshown) for transferring loads between concrete slabs are configured tobe closely received in each sheath 2300.

Form 2200 differs from previously described embodiments in that form2200 does not provide a slot for receiving a load plate. Rather, asdescribed below, form 2200 provides for mounting sheath 2300 thereon.Preferably, form 2200 has sets of pre-drilled holes 2205 for receivingfasteners for fixing sheaths 2300 on form 2200, spaced according towhere sheaths 2300 are desired. As with slots 2060, spacing of the setsof holes 2205 corresponds to loading conditions anticipated for the loadplates (not shown) ultimately installed in adjacent concrete slabs.

Sheath 2300 has a mounting plate 2305 that provides for fixing sheath toform 2200 so that the interior 2320, which is configured to receive aload plate (not shown), is disposed toward form 2200, preventing pouredconcrete from entering. To this end, mounting plate 2305, preferably,has througbores 2310 that receive threaded fasteners 2315 for engagingholes 2205. Mounting plate 2305 also may be configured to provideintegral protrusions or pins (not shown) for engaging holes 2205.

While form 2200 is described as having the “female” components andsheath is described as having the “male” components of whatever fixingconvention is employed, such may be reversed. Other mounting conventionsmay be used that are appropriate and render fixation easy andinexpensive.

Referring to FIG. 33, an embodiment of another method 2400 of formingconcrete configured according to principles of the invention includes: astep 2405 providing a form configured to secure a portion of the sheaththereto, thereby orienting an exterior of the sheath for contactingconcrete when poured thereon; a step 2410 of positioning the form toreceive concrete; a step 2415 of securing the sheath to the form; a step2420 of pouring a first volume of concrete on the form and the exterior;and a step 2425 of curing the first volume of concrete and defining afirst slab.

Referring also to FIG. 30, step 2405 of providing a form 2000 configuredto secure a portion of the sheath thereto may involve providing the formwith slots 2060 for closely receiving the outer perimeter at the openingor mouth of the sheath, or a mounting plate defining same, such that theopen end of sheath interior 2120, which is configured to receive a loadplate (not shown), is disposed toward form 2000, preventing pouredconcrete from entering. Thus, the poured concrete would contact and cureor adhere to only the exterior of sheath 2100, leaving interior 2120free of any concrete that could interfere with desired mobility of aplate in sheath 2100.

Referring to FIG. 32, step 2405 of providing a form 2200 configured tosecure a portion of the sheath thereto alternatively may involveproviding the form with pre-drilled holes for receiving fasteners forfixing sheath thereto. Other affixation conventions may be employed asappropriate, easy to use and economically sensible.

Step 2410 of positioning the form to receive concrete is conventional.

Referring again to FIG. 30, step 2415 of securing the portion to theform, where form 2000 has slots 2060 for receiving sheath 2100, involvesinserting sheath 2100 in slot 2060. Where sheath 2100 has a mountingplate 2105, step 2415 would involve inserting mounting plate 2115 inslot 2060.

Steps 2420 and 2425 are conventional and described no further.

Referring to FIGS. 33 and 34, another embodiment of an apparatus forforming concrete configured according to principles of the inventionincludes a form 2500. Like form 100, form 2500 has a side surface 2505,a top surface (not shown), a back surface 2515 and a bottom surface (notshown). Form 2500 has a chamfer (not shown) that is comparable tochamfer 135 between top surface (not shown) and back surface 2515. Sidesurface 2505 and chamfer (not shown) define a top surface width (notshown)that is comparable to top surface width 143. Preferably, a releaseoverlay 2560 comparable to release overlay 160 is disposed on sidesurface 2505.

Form 2500 has a slot 2510 that closely receives a plate, such as plate2600. Slot 2510 is constructed so as to encourage proper assembly ofform 2500 and plate 2600, as shown in FIG. 34. Proper assembly promotesproper orientation of form 2500 so that concrete is poured againstrelease overlay 2560, not back surface 2515. Proper orientation of form2505 relative to a concrete pouring area facilitates ready release ofform 2500 from the concrete when sufficiently cured, and promotes acleaner or more finished joint surface.

Accordingly, slot 2510 is configured to enable or promote completeinsertion of plate 2600 therein along direction 2520, and incompleteinsertion when attempted in the opposite direction. Thus, a concreteworker may readily observe upon insertion whether plate 2600 is fullyreceived in slot 2510 and confirm that form 2500 is properly oriented.To this end, slot 2510 may be configured to have at least two sections,a first section 2523 and a second section 2525. First section 2523 isproximate to back surface 2515, defining a lip 2527 at the intersectiontherewith. Second section 2525 is proximate to side surface 2505 and,being larger than first section 2523, defines a shoulder 2530 at theintersection therewith.

FIGS. 33 and 34 also show another embodiment of an apparatus fortransferring loads between concrete slabs configured according toprinciples of the invention including a plate 2600. Like plate 300,plate 2600 has a first portion 2615 and a second portion 2620,delineated by a plane 2621. First portion 2615 may be untreated. Secondportion 2620 may have an elastomer coating 2625 that is comparable toelastomer coating 325. Second portion 2620 also may have one or moresurfaces 2640 on which edge banding 2645, comparable to edge banding1005, may be disposed.

First portion 2615 is configured to be closely received in slot 2510 andpromote complete insertion of plate 2600 therein along direction 2520,and incomplete insertion when attempted in the opposite direction. Tothis end, first portion 2615 preferably has a like number ofcorresponding segments as slot 2510 has sections. Thus, first portion2615 may have a first segment 2630 and a second segment 2635 thatrespectively correspond to first section 2523 and second section 2525.

When inserted properly, first portion 2615 nests snugly in slot 2510 andplate 2600 appears to be fully received, as shown in FIG. 34. If plate2600 is inserted into slot 2510 in an incorrect direction 2521 oppositeto direction 2520, first segment 2630 may be received in first section2523 of slot 2510, but second segment 2635 is not received in secondsection 2525 and plate 2600 does not appear to be fully received, asshown in FIG. 35.

When plate 2600 is properly received in form 2500, as shown in FIG. 34,second segment 2635 abuts shoulder 2530 preventing passage of plate 2600through form 2500. When incorrect insertion of plate 2600 is attempted,as shown in FIG. 35, second segment 2635 abuts lip 2527 preventingcomplete reception of plate 2600.

Referring to FIG. 34, the positive stop provided by second segment 2635and shoulder 2530 also operates to prevent coating 2625 and/or edgebanding 2645 from accidental dislocation from plate 2600. While coating2625 and/or edge banding 2645 are dimensioned to prevent passage throughslot 2510, the weak bond between coating 2625 and/or edge banding 2645and plate 2600 could allow for separation if subjected to especiallyvigorous insertion. The positive stop prevents even excessive insertionfrom stripping off coating 2625 and/or edge banding 2645.

The sectioned slot 2510 and segmented first portion 5615 also promoteready form removal from a cured concrete slab. While a concrete slabcures, form 2500 and plate 2600 are positioned as shown in FIG. 34. Oncecured, form 2500 must be removed. Plate 2600, having been snuglyinstalled in form 2500, is not easy to remove. Therefore, reducing thecontact or interference fit between first portion 2615 and slot 2510reduces the force necessary to remove form 2500 from the slab. To thisend, rather than having to pull first segment 2630 of first portion 5615through an entire form 2500, first segment 2630 only has to clear fromfirst section 2523 of slot 2510, reducing the overall amount of effortneeded to remove form 2500 from the cured concrete slab.

To promote even greater ease of form removal, either or both of secondsegment 2635 and second section 2525 may have curved or radiusedsurfaces (not shown). Where both of the second segment 2635 and secondsection 2525 surfaces are radiused, such should be complementary. Thepreferred radius is 18 inches.

FIGS. 36-67 show alternative embodiments of an apparatus fortransferring loads between concrete slabs configured according toprinciples of the invention. In each figure, “A” generally designates aplate and “B” generally designates an elastomeric coating with orwithout edge banding, as described herein. As with the embodimentsdescribed above, a first concrete slab is intended to adhere to only thecoating and/or edge banding, while a second concrete slab is intended toadhere to only the portion of the plate that is not coated or edgebanded. Thus, the joint between the first and second concrete slabscorresponds with line defined by where coating and/or edge banding Bdiscontinues on A.

As used herein, “normal” obtains its customary meaning, perpendicular toa surface or the tangent of a curved surface. “Predominating normal” orcognates thereof refers to an average of the normals of a nonuniformsurface.

Referring to FIGS. 38, 39, 40, 41, 52, 53, 60, 61 and 64-67, someembodiments have coated portions of the plate A that have surfaces that,when emplaced, are not predominantly normal to the joint betweenconcrete slabs. When the concrete cures, the concrete shrinks away fromthe surface along that predominantly normal direction. A void formsbetween the concrete and the apparatus corresponding to the amount thatthe concrete shrunk. When the first and second slabs move horizontallyalong the joint, the void provides clearance for plate A to movetherein, thus preventing compressive forces from growing to an amountsufficient to cause localized concrete failures. The amount that theslabs may move relatively along the joint is a fraction of the amountthat the concrete shrinks away from the surface in the predominantlynormal direction, according to standard trigonometric principles.

Referring to FIGS. 36, 37, 46, 47, 50, 51, 54, 55, 58, 59, 62, 63, 64and 65 some embodiments have coating and/or edge banding having athickness or resiliency that differs according to location on surface onwhich the coating and/or edge banding is disposed. In addition to anyvoid that develops between the concrete and the coating and/or edgebanding, a moving concrete slab also may compress the coating and/oredge banding without developing compressive forces to an amountsufficient to cause localized concrete failures. Similar to the above,the joint travel distance may be tailored by fine tuning the coatingand/or edge banding thickness or resiliency.

Another embodiment provides for tailoring the joint travel distance bycoordinating both the surface, hence predominant normal, and the coatingand/or edge banding thickness or resiliency.

The invention is not limited to the particular embodiments described anddepicted herein, rather only to the following claims.

1. Apparatus for forming concrete comprising a form having a slotconfigured to closely receive a plate in only one direction. 2.Apparatus of claim 1, wherein said slot has a first section and a secondsection that is larger than said first section.
 3. Apparatus of claim 2,wherein at least one of said first section and said second section hascooperating surfaces that correspond to a direction in which said slotreceives the plate.
 4. Apparatus of claim 2, wherein said first sectionand said second section define a shoulder for contacting a part of theplate and preventing passage through said slot.
 5. Apparatus of claim 2,wherein said second section defines a radius that promotes ready removalof a plate therefrom.
 6. Apparatus of claim 2, wherein said form has asurface for receiving concrete and said second section is interposedbetween said first section and said surface.
 7. Apparatus of claim 1,further comprising a release layer on said form.
 8. Apparatus of claim7, wherein said release layer is constructed of phenolic paper, kraftpaper, acrylic, latex, melamine, Formica®, foil, oil, high densityoverlay, metal, wood veneer or combinations thereof.
 9. Apparatus ofclaim 1, wherein said form is constructed of oriented strand board,dimensional lumber, particle board, metal, plastic, cardboard, fiberboard, polyurethane foam, Styrofoam® or combinations thereof. 10.Apparatus of claim 1, further comprising a plate configured to beclosely received in said slot.
 11. Apparatus of claim 2, furthercomprising a plate configured to be closely received in said slotwherein said plate has a first portion and a second portion, whereinsaid second portion has a first segment configured to be received insaid first section and a second segment configured to be received insaid second section.
 12. Apparatus of claim 11, wherein said secondsegment defines a radius that promotes ready removal of said plate fromsaid form.
 13. Apparatus of claim 11, wherein said second sectiondefines a radius that promotes ready removal of said plate therefrom.14. Apparatus of claim 12, wherein said second section defines a secondradius complementary of said radius.
 15. Apparatus for transferring aload between a first concrete slab and a second concrete slab, defininga joint, comprising a plate having a first portion and a second portion,wherein said second portion has a first segment and a second segmentthat is larger than said first segment.
 16. Apparatus for transferring aload between a first concrete slab and a second concrete slab, defininga joint, comprising: a plate having a surface; and edge banding disposedon said surface that is compressible and/or resilient; wherein an amountthat said edge banding is compressible and/or resilient in a directionnormal to said surface differs according to location on said surface.17. Apparatus of claim 16, wherein said edge banding has a thickness ina direction normal to said surface that differs according to location onsaid surface.
 18. Apparatus of claim 16, wherein said surface is notpredominantly normal to the joint.
 19. Apparatus of claim 16, whereinsaid edge banding is configured to provide an amount of resilience,whereby the first concrete slab, when cured, may move a distancerelative to the plate.
 20. Apparatus of claim 19, wherein said amount ofresilience results in the distance being sufficient to preventcompression between the first concrete slab and said apparatus fromachieving an amount sufficient to cause local failure in the firstconcrete slab.
 21. Apparatus of claim 19, wherein said surface is notpredominantly normal to the joint and has a configuration such that,when the first concrete slab cures, the first concrete slab shrinks awayfrom said apparatus by a second distance normal to said surface, wherebythe first concrete slab, when cured, may move relative to the platealong the joint by a third distance; and said configuration of saidsurface and said amount of resilience of said edge banding arecoordinated to result in a sum of the distance and the third distancebeing sufficient to prevent compression between the first concrete slaband said apparatus from achieving an amount sufficient to cause localfailure in the first concrete slab.